Can't open Asus RT-AX88U Web UI when connected via VPN

[Ferrarista]

I have an Asus RT-AX88U in PPPoE mode set in my hometown. On this router, I have set an OpenVPN server. Normally, when connected to this VPN from any other internet connection, I can get automatically to the ASUS Web UI by opening the address 192.168.2.1. This happens almost always, except in the case when I am in my second residence place and I am connected to the Internet via a Speedport Smart 3 (Deutsche Telekom). In practice, when I am connected to the Internet via the Speedport and I type 192.168.2.1, the browser shows the config page of the local modem instead of the Web UI of the remote Asus router. In any other case (i.e. when connected to the VPN server via any other internet connection) I correctly get the Asus Web UI. What could be the reason of this?

 

[cptnoblivious]

Are both networks 192.168.2.x?

 

[Ferrarista]

Do you mean the remote and local networks? Yes, the address of the two routers in both networks is 192.168.2.1.

 

[Ferrarista]

up

 

[RMerlin]

You have overlapping network IP ranges. The simplest workaround is to try reaching your router's webui using the tunnel endpoint IP instead of the LAN IP (i.e. try with 10.8.0.1).

 

[Ferrarista]

I tried but it does not work (the endpoint is 10.8.0.2, but i tried also with 10.8.0.0 and 10.8.0.1). This behavior is anyway strange because in the past it was working as expected (i.e. I was getting the Web UI of the modem when opening 192.168.2.1 while connected to the VPN). What has changed since then is the firmware of the router that is now the one by Merlin.

 

[Ferrarista]

up

 

[cptnoblivious]

I tried but it does not work (the endpoint is 10.8.0.2, but i tried also with 10.8.0.0 and 10.8.0.1). This behavior is anyway strange because in the past it was working as expected (i.e. I was getting the Web UI of the modem when opening 192.168.2.1 while connected to the VPN). What has changed since then is the firmware of the router that is now the one by Merlin.

You already have your answer.

Both networks have the same IP range. Change one of them to a different network like 192.168.3.x/24